American gymnast Simone Biles will not defend her individual all-around Olympic title in Tokyo tomorrow.In a statement posted on Twitter, USA Gymnastics confirmed Biles would not be appearing in the individual all-around event."After further medical evaluation, Simone Biles has withdrawn from the final individual all-around competition at the Tokyo Olympic Games, in order to focus on her mental health," the statement said."Simone will continue to be evaluated daily to determine whether or not to participate in next week's individual event finals. We wholeheartedly support Simone's decision and applaud her bravery in prioritising her wellbeing. Her courage shows, yet again, why she is a role model for so many."The 24-year-old Biles endured a difficult day at the Ariake Gymnastics Centre yesterday. She pulled out of the artistic gymnastics team final after recording her lowest Olympic vault score – 13.766. Biles revealed she withdrew to "focus on my mental health."

The US went on to take the silver medal in her absence, losing out on gold to the Russian Olympic Committee. Team GB finished third to earn a historic bronze medal.

Biles later spoke more on her decision to pull out of the competition.

"After the performance I did, I just didn't want to go on," she said. "I have to focus on my mental health. I just think mental health is more prevalent in sports right now.

"We have to protect our minds and our bodies and not just go out and do what the world wants us to do. I don't trust myself as much anymore. Maybe it's getting older. There were a couple of days when everybody tweets you and you feel the weight of the world.

"We're not just athletes. We're people at the end of the day and sometimes you just have to step back. I didn't want to go out and do something stupid and get hurt. ​I feel like a lot of athletes speaking up has really helped."

Sarah Hirshland, chief executive of the US Olympic and Paralympic Committee, has been among those to praise Biles, writing: "We applaud your decision to prioritise your mental wellness over all else and offer you the full support and resources of our Team USA community as you navigate the journey ahead."

Biles is also the reigning Olympic champion in the vault and floor. She had been due to compete in the vault and uneven bars on Sunday August 1st, before the floor on Monday August 2nd and balance beam on Tuesday August 3rd.

The gymnastics icon has not yet confirmed whether she will still be contesting these events.